Lightning-arrester



(No Model!) 2 Sheets-Sheet 1.

B; THOMSON. LIGHTNING ARRESTER.

No. 470,721. Patented Mar. '15, 1892.

m vmron WITNESSES:

' L'Ziiuv Thornsarv ATTORNEY.

.(No Model.) I 2 Sheets--Sheet 2.

E. THOMSON. LIGHTNING ARRBSTER.

No. 470,721. Patented Mar. 15, 1892'.

my Elzhu A TTORNEY.

UNITED STATES PATENT OFFICE.

ELIIIU THOMSON, OF LYNN, MASSACHUSETTS, ASSIGNOR TO THE THOMSON- HOUSTONELECTRIC COMPANY, OF CONNECTICUT.

LlGHTNlNG-ARRESTER.

SPECIFICATION forming part of Letters Patent No. 470,721, dated March15, 1892. Application filed December 26,1889. Serial No. 335,063. (Nomodel.)

To all whom it may concern:

Be it known that I, ELIHU THOMSON, a citizen of the United States, and aresident of Lynn, in the county of Essex and State of Massachusetts,have invented certain new and useful Improvements in Lightning-Arrestersand Static-Discharge Protectors, of which the following is aspecification.

My invention relates to electrical apparatus to in which anelectro-inagnet is employed for disrupting or removing an electric areformed between two points or electrodes included in an electric circuit;and it consists more particularly in the relative disposition or the ar-I 5 rangeinents of the electrodes and the arc-rupturing magnet ormagnetic field.

My invention is applicable to lightningarresters, static-dischargeprotectors, electric fuses, or any other electric apparatus wherein twoconducting bodies or electrodes are liable to have an are formed betweenthem which it is desired to suppress or remove immediately.

I have in the present specification described my invention as carriedout in connection with a lightning-arrester or static-dischargeprotector, the electrodes of which, being-placed in close proximity, areliable to have an are formed between them and maintained by the currentof the dynamomachineorothersource of the circuit to which they areapplied after the passage of a lightning or static discharge from one tothe other of such electrodes. As before stated, however, my invention isap- 3 5 plicable likewise to any other device wherein an electro or anyother magnet is applied to disrupt or put out an electric are betweentwo electrodes.

The object of mypresentinvention is to increase the power of disruptionof the magnetic field and thereby to enable the apparatus to work moreetficiently under conditions where a powerful arc would be apt to followthe lightning or static discharge or to ensue upon other changes in theconditions of the circuit or the apparatus-as, for instance, by therupture of a fuse in a safetyfuse device-in which case an arc wouldfollow and be maintained across the electrodes or conducting-blocks inwhich the ends of the fuse are held.

My invention consists, first, in the combination, with electrodesconnected toan electric circuit supplied or connected with a source ofelectric energy suflicient to main- 5 5 tain an electric are once formedacross the space between said electrodes, of an arc-rupturing magnet ormagnets having said electrodes disposed in a portion of the magneticfield or space containing lines of magnetism passing from one pole toanother of the magnet in such manner that the line joining saidelectrodes shall be parallel to the lines of the magnetic field whichoperates to rupture the are.

My invention consists, further, in giving such a polarity to saidmagnetic field that the tendency shall be to displace the arc in anupward direction. The effect of so disposing the electrodes is that anyare forming between them will be displaced in the magnetic field in adirection to elongate its path very greatly while still remaining in.the field, thereby impelling the discharge or are to take up a movementin the field, whereby it shall inclose such field in a widening are orcircle.

My invention consists, further, in the combination, with thearcing-electrodes and their disruptingmagnets, of one or more arediverting or interrupting plates or vanes in the path of the wideningare, as will be hereinafter more fully described.

My invention consists, also, of other details of construction anddisposition of parts to be hereinafter more particularly described, andthen specified in the claims.

In the case of the application of my invention to a lightning-arresterthe relative disposition of the electrodes and the arc-rupturing magnetmaybe described as one in which the electrodes are presented or directedtoward one another, so that the lightning or static discharge will takeplace in the general direction of the lines of force of thearc-rupturing magnetic field or in a line coincident o with or parallelto the line joining the poles J of the magnet in case the action of bothpoles of the magnet is resorted to for the purpose of disrupting orputting out the are.

In the accompanying drawings, which illustrate the application of myinvention to a lightningarrester, Figure 1 shows a side ele- IOO whichthe poles N S are mounted or of which they form extensions. The coils COmay be included in an electric circuit, in which c'i1rrent flowsconstantly or in which current is made to flow temporarily only when theoccasion arises for disrupting the are. The poles N S are made ofopposite polarity by the manner of winding the coils or of causing thecurrent tocirculate through them. In the case of a lightning arrester,where the coils O C are included in the path of the discharge, care mustbe taken to so wind or connect :the coils to the circuit that thecurrent circulating through such coils and across the discharge pointsor electrodes D, constituted between the poles, shall set up poles ofopposite name at N S. The dischargepoints D are mounted on the poles, asshown, and are preferably electrically connected to or carried by them,though this course is not essential to my invention, the prime objectbeing to locate them withinthe field, and preferably in the middlethereof, in such manner I that the points or discharge-surfaces shall bepresented to one another on a line joining the magnet poles orparallelto the magnetic lines of 'force joining such poles. To attainthe best construction and action the poles N S are separated by a smallspace, so that the electrodes D, existing as little buttons of metal,such as copper or other material secured to the poles N S,"may comewithin a very short distance of each other.

In prior patented devices in which an arcrupturing magnet is employedthe arcing electrodes have been disposed in the arc-disrupting field insuch way that the line joining the conducting-faces which are presentedto one another, and from one to the other ofwhich the electric circuitis normally formed,

is a line transverse to the lines of magnetic force or to the linejoining the poles of the arc-disrupting magnet. In my present in-.'vention, however, the line is one such that in the case of alightning-arrester the discharge shall occur in the line of the magneticfield between which the discharge points or electrodes are placed,instead of transversely to such field, the effect being that the arcfollowing a discharge willbe contorted or twisted out of its straightpath to a rotary path or position which will make it include themagnetic field or encircle the same. This distortion of the arc, to makeit include a path of considerable length or extent, is facilitated bythe addition of devices, which will be hereinafter described, but whichare not essential to the operation of the invention.

In the case of a lightning-arrester such as shown herein it is well tohave one of the coils, as O, in a circuit or energized from the line, soas to keep up a certain magnetization between the poles N S. I haveshown a coil 0 connected into a line passing between 0 d, the coil 0having its inner terminal connected to the core or magnetic bar on whichit is wound and which, therefore, is in connection with the right-handdischarge point or electrode at D. The line 0 d may be any lighting orpower line or other electric line which it is desired to protect or abranch from the same. The faces of the poles N S presented under thesecircumstances will, when the coil C is traversed by current, be verystrongly magnetized, and to enhance this the lower ends of themagnetized bars on which the polar extremities are supported are broughtnear together with an interposed insulation below, as at I, thearrangement shown being virtually a horseshoe-magnet whose bent portionis separated and insulated. The discharge point or electrode D at theleft, Fig. 1, and carried by the pole N, is connected to earth at Ethroughthe coil 0' or to another point, as will be presently described,for carrying off the static discharge. The electrical connection may beformed by connecting one end of the coil 0 to the iron' bar. on whichthe pole N is mounted, while the other or outer end of such coil isconnected to the earth-plate E.'

It is advisable in some cases to have a small discharge-space, as at 0t,between the outer wire of the coil 0' and the core on which it is wound,though this is not necessary in all cases. This discharge-space simplyallows a quick or static discharge to leave the discharge point carriedby N without going through the, coil 0', which might oppose its passage.A similar arrangement might be provided for the coil 0, it being a sortof disruptive shunt; but these form no features of my present invention.

While the devices as thus organized would be very effectual indisrupting or putting out any are which might form across the electrodes of the lightning-arrester, I sometimes prefer to prevent theformation of a dischargecircuit or an are at any other point, exceptingat the electrodes D, by adding a facing of insulation to each of thepoles N S, as indicated at M. This facing may be of mica or slatetransverse to the line of the are which will be formed when theelectrodes are arranged as described. These vanes, plates, orarc-diverting barriers are shown more clearly in Fig. 2 as radiatingoutward from the center at which the electrodes D are located in themiddle of the insulating facings or disks M, covering the poles. I' alsoprefer to provide the electrodes D, though it is not essential to do so,each with a projection or extension 6 or e, extending laterally from theelectrode outward toward the edge or confines of the magnetic fieldformed between the poles. These extensions are made of metal, and whenthe winding of the coils O O and the arrangement of magnetism of thepoles is such as to force the arc upwardly are carried downwardly, asindicated in Figs. 2 to 6, inclusive. The faces of these extensions orprojections lie a little back of the discharge surface or point of theelectrodes D, so that the latter are nearer together than the extensionsfrom them. The extensions 6 e from the discharge-points do not projectradially outward on coincident radial lines, but as shown in Fig. 2,while the extension 6 proceeds radially downward to the right. Theprojection e proceeds in a divergent path, as shown by the dotted lines,or to the left. \Vhile, therefore, the discharge points or electrodesare directly opposite to one another, the projections or extensionstherefrom are inclined away or project in divergentradial paths. Theutility of this will be seen presently.

It should be understood that the plates or vanes V and extensions e eare not essential features of my invention, though they are of value asadjuncts to it, the main principle being to cause the discharge to passfrom one electrode to the other in the middle of the field or on a line,as before described, which shall be coincident with or parallel to thatjoining the polar faces of the arc-disrupting magnet, or, in otherwords, on a line substantially parallel to the magnetic axis of thearcdisrupting magnet, and thereby be acted on powerfully and take thecourse whichwill be described in case an are forms.

To show the operation of the device, Fig. 3 exemplifies the positiontaken by an are immediately after a discharge has occured between thepoints D upon the poles. The dischage does not remain for an instant atthe center point, but separates at once radially outward in alldirections and runs down the discharge points or extensions 6 e, which,diverging relatively, lead the heated gas at each side to a distance ofseparation, while the arc or discharge plays outwardly in the spacebetween the poles or between the insulated faces M, surrounding orfacing these poles. The radial wings or vanes between theinsulating-faces, when they exist, as in Fig. 5, act as are interruptingor diverting plates or barriers to cut up or further elongate thearcdischarge, which is being driven outward in that the direction ofcurrent in them will be such as to produce a field which will cause thedischarge or are to be driven upward or into the position or form shownin Figs. 3 and 5, so as to be interrupted or broken up by the rings orvanes. If the discharge were driven downward instead of upward, thespace traversed by the are between the ends of the extensions of theeiectrodes obviously would not be so long and the action would be lessefficient.

Fig. 4: shows a lateral view of the course which would be taken by thearc in Fi 3, leaving one discharge-point to go to the other. It isturned about in the course there indicated, and if the extensions 6 care properly located will not continue discharging from thedischargepoints at all, but will follow down the extensions to theirextremities.

Modifications in the shape of the parts, not departing from theessential features of the invention, maybe made. Thus in adding thevanes or radial project-ions V between the faces M they may be made tostill further separate the heated gases while being driven outward bygiving them the form shown at V in Fig. 6, where they are shown enlargedor thickened at their outer ends, so as to contract the openings orincrease the distance between the same outside the wings or vanes. Theconstruction thus produced, it will be seen, affords virtually a ring orenvelope of insulating material having a number of discharge-openingsalmost of the character of jets around the central discharge points orelectrodes D, so that the heated gases being driven outward are expelledin separate streams and cannot reunite to continue the arc-discharge.

Fig. 7 shows the discharge-points at D, made in one piece with the polesN S and such poles covered all over with a coating of insulatingmaterial, which, however, is not herein claimed.

Fig. 8 shows the presentation of the poles N S as blunted cones, theirextremities making the discharge-points or being capped with copperbuttons for the same purpose, while over each pole is fitted a flangedcap or hollow conical shell with flanges M M, which enable the dischargeto play out from between the poles into the free air beyondwithoutreaching or settling down upon the magnet-poles themselves.

Fig. 9 shows the separation of the dischargepoints into two sets D D inseries, with an intermediate insulating-plate M interposed between-thetwo sets of discharge-spaces. In this case two arcs are formed and twospaces for disruption are provided in the same field.

fect of having a number of disruptive points.

in series. When a number of dischargespaces in series are thus provided,the effects are intensified to a great degree, owing to the fact thatany static disruptive discharge will leap a number of separate spaces ofa given width arranged in series more readily than it will pass over asingle space whose width is the sum of the small spaces.

Fig. 10 shows the interposition between the two sets of discharge-pointsof a mass of iron G, intended merely to 'act as a conveyer of themagnetic force. This figure illustrates how it would be possible to puta number of discharge-points in series, since the magnetic bar orportion G might even be wound with energizing-coils, which wouldincrease the magnetization, though generally it would be magnetizedfrom-the poles N S to a sufficient extent. In this case the insulatingdisks or washers face the polar portions and are indicated by theletters M M M M Modifications in the forms and disposition of thedischarge-points themselves in relation to each other, not departingfrom the essence of my invention, may be made.

The action of the extensions 6 e, in connection withtheinterrupting-plates,willbeclearly understood from Figs. 3 and 5. Theextensions act to cause the arc to be first formed at points somewhatbelow the level of the electrodes D, where they are nearest together;but owing to the action of the magnetic field the arc following isinstantly thrown upward, and thus caused to traverse a long space, inwhich are interposed the vanes or wings V. Being thus prolonged orextended, it may be broken with comparative ease.

What I claim as my invention is 1. The combination, with anarc-rupturing magnet, of the arcing electrodes connected to a circuitsupplied from a source of energy sutficient to maintain a continued areonce formed from one to the other and presented to one another on a lineparallel to the lines of magnetism or line joining the poles of saidmagnet.

2. The combination, with the arc-rupturing magnet and the arc electrodespresented toone another on a line joining the magnetpoles, of one ormore arc-diverting plates or vanes arranged in the arc of a circlearound said electrodes and in planes substantially parallel to the linejoining said electrodes.

3. The combination, with the arcing electrodes or abutments, of anarc-disrupting magnet tending to give the arc arotary or twisted pathtransverse to the lines of magnetic force and surrounding them, and oneor more barriers or plates disposed in a manner to oppose the freemovement of such rotary arc and cause it to beinterrupted or to assume amore lengthened path, substantially as and for the purpose described.

4. The combination, with the arc-rupturing magnet having poles broughtinto close proximity and adapted to produce an arc-rupturing magneticfield in which the lines of ,force may pass directly or withoutdiversion from one pole to the other, of arcing electrodes located at ornear the center of the magnetic space between the poles of the magnetand presented or directed toward one another on a line joining saidpoles and substantially parallel to the axis of the magnetic field orlines of force flowing between the poles, as and for the purposedescribed.

5. The combination, with the arcing electrodes and arc-rupturing magnet,of a surrounding cage or barrier arranged around the electrodes andprovided with a number of discharge-openings.

6. The combination, with the arc-rupturing magnet and two ,or more setsof arcing electrodes arranged in series between the magnet-poles, of anintermediate conveyer of magnetism, as and for the purpose described.

7. The combination, with the opposed magnetic poles, of the dischargepoints or electrodes located between the same and provided withextensions for leading the discharge outward in difierent directionstoward the confines of the magnetic field.

8. The combination,with the magnetic poles and the discharge points orelectrodes located between the same, of disks or plates of insulatingmaterial over the pole-faces and connecting vanes or wings of micabetween such plates.

9. In a lightning-arrester, two or more sets of discharge points orelectrodes arranged in and in line with one another substantiallyparallel to the lines of magnetic force or the magnetic axis of suchfield.

10. The combination, in a lightning arrester, of two or more sets ofelectrodes arranged in series, means for diverting or forcing the arclaterally outward, and are diverting or interrupting plates contiguousto the spaces between the several sets of electrodes and placed in thepath of the are following any discharge. 7

11. The combination, in a lightning arrester, of two or more sets ofdischarge points or electrodes placed in series, in combination with anarc-rupturing magnet, between whose poles the said two or more sets arearranged in a line parallel with the line joining said poles.

placed in an arc-rupturingfield,of extensions projecting toward theconfines of the field, but on divergent lines.

14. The combination, in a lightningarrester, of arc-rupturing magnetormagnets having their poles brought close together, anddischarge-electrodes electrically connected to the poles and directedtoward one another in the magnetic field or space in which the lines ofmagnetic force pass from one pole to the other, as described, and sothat the discharge from one to the other will take place in a linecoincident with or parallel to the line joining the pole-faces.

15. The combination, substantially as described, of discharge points orelectrodes D,

connected to an electric circuit supplied With ELIHU THOMSON.

Witnesses:

JOHN W. GIBBONEY, ALBERT L. ROHRER.

